Data is required to be written and read in many sub-systems within computer systems. For example, in magnetic storage systems, data is written to a magnetic recording medium by a transducer which leaves a magnetic signature within the magnetic material of the recording medium. The data is then read from the magnetic material at a later stage by a further transducer or in many cases the same transducer which detects the magnetic signature within the magnetic recording medium. Components within a computer system also pass data in via bus systems. Such bus systems may interconnect internal adaptor cards, memory, video or peripheral host adaptor cards for example. Other bus systems may interconnect internal or external peripheral units such as scanners, printers or magnetic storage devices for example. A first component writes the data to the bus in the form of a series of changes in voltage or current. Components requiring the data read the data from the bus by detecting these changes.
In all aspects of computer technology there is a continuous requirement for more data storage, for data to be processed faster and for it to be communicated faster. In presently known magnetic storage devices, data bits are stored on the magnetic storage medium using a variety of methods. Such methods include the presence or absence of a magnetic signature on a given area of the medium, analogue frequency representation of corresponding data bits “1” and “0” or in longitudinal patterns of magnetic particles with North-South or South-North magnetic polarity. Such an arrangement of representative data bit “1” and “0” in accordance with the longitudinal magnetic orientation. In order to increase the amount of data stored on a given area of magnetic medium, the data footprint size must be decreased, the number of recording sides must be increased and the recording tracks must be decreased in width and located in closer proximity to each other. However as the areal density increases so does the likelihood of adjacent bits degrading each other's magnetic signatures. In addition, if the bit area is to be reduced, the accuracy of the magnetic head and its positioning system must be correspondingly increased. A further problem for present magnetic storage devices is performance. Faster reading and writing operations can increase performance. Performance increases can be achieved by increasing the speed of which the media surface (also known as the substrate) is passed under the transducer used for writing and reading the magnetic data signatures. Currently, data words are written and read sequentially. Performance increases can be achieved by increasing the rate at which the substrate is passed under the transducer used for writing and reading the magnetic data signatures. However by writing and reading whole data words at a time would result in a significant performance.
In buses of the type presently known bits are transmitted by being written onto the bus at a first location by a first component in the form of the presence of an electric voltage or current and by being read at a second location by a second component which detects changes in the electric voltage or the direction of the electric current. The time interval required to be left between bits is dependent on the signal degradation which in turn is dependent on the cable length, signal shaping and electrical characteristics. As the bus length is determined by several factors, such as signal shaping and electrical characteristics, the achievable bit rate on the bus is limited. Therefore in order to increase the data throughput on a bus it is necessary to increase the bus size, i.e. provide further wires or enhance signal processing, etc. This requires more equipment which increases the cost and the complexity of the bus.
It is an aim of the present invention to alleviate some of the problems described above with conventional data reading and writing methods.